I'm sure other cards will support it.
In the future other cards will support it. But right now, the only one that does is the 960 GTX, and it isn't just a simple driver/firmware change that will add support to existing cards, but actual hardware change. So as stated, right NOW if you want 4k Netflix and other support for 4k video, the ONLY card is the 960 GTX (otherwise you need a beefy CPU since nothing else support H.265 hardware acceleration).
HVEC acceleration is available on Haswell and Broadwell (5th Generation Intel Core Processors w/ HD graphics 5500, HD graphics 6000, Iris graphics 6100)
https://communities.intel.com/thread/59216
Since there isn't that much 4K content yet, it is best to hold off on the video card and wait for something better than the 960.